President Barack Obama’s pledge that the government will no longer be the keeper of a vast trove of Americans’ phone call records is bound to touch off a political battle among telecom providers, privacy advocates and congressional lawmakers about whether that can work and who should be in charge of holding the data.

Obama announced Friday he would leave it to the intelligence community and the attorney general to determine within 60 days whether it would be providers like AT&T and Verizon, a new third-party clearinghouse or some other mechanism maintaining access to records about calls made to, from and within the United States.

The president also raised the possibility that the government could rely on “a combination of existing authorities, better information sharing, and recent technological advances” to replicate the capabilities it currently has under Section 215, which the president described as essential in a post-9/11 world to fight terrorism.

“But,” he added, “more work needs to be done to determine exactly how this system might work.”

Moving responsibility for phone-record retention to the private sector is likely to stir up tensions. Telecom companies have long balked at the suggestion that they hold the metadata, saying it would create new costs and liabilities for them. Civil liberties groups fret the privacy implications of industry holding the data, while leading lawmakers with oversight of the intelligence community have said the government should keep it.

Other questions include how a third-party clearinghouse for metadata might work. Any of the options could require congressional approval.

Obama’s announcement comes about a month after a task force he appointed to study surveillance programs recommended the NSA shed its vast database of phone call logs, arguing it had yielded only “modest contribution to the nation’s security.” The group presented some alternative options, including a law to require that telecom companies hold the data; new Federal Communication Commission rules setting longer data retention periods for telecoms; or the creation of a new third party clearinghouse-like entity to hold the information.

Behind the scenes, the nation’s top telecommunications providers balked at any administration plan that might make them hold metadata on behalf of the government. Most companies have said little about the proposal; AT&T on Friday said only it would “review the proposal and look forward to working with Congress and the Administration.” But the wireless industry’s top trade association, CTIA, has openly criticized the idea.

Jot Carpenter, vice president of government affairs for CTIA, said after the president’s speech the group would work with regulators to strike the right balance between security and privacy, but added “this balance can be achieved without the imposition of data retention mandates that obligate carriers to keep customer information any longer than necessary for legitimate business purposes.”

Moving metadata to the telecom companies, the industry argues, would be fraught with challenges. The companies feel it could expose them to new legal liabilities, a sentiment echoed by privacy advocates who say having companies hold the records could expose the data to lawsuits or malicious hackers.

“There are many technological, legal, security and privacy complexities involved in any proposal to change how any database is stored and accessed,” said one telecom executive this week as different stories emerged about the president’s plans.

Others say it could cost the U.S. government dearly to make the switch. The administration actually studied the proposal as far back as 2011 and determined it could cost “tens of millions” of dollars to implement, according to Senate aides. Leading lawmakers on key intelligence committees, including Rep. Mike Rogers (R-Mich.) and Sen. Dianne Feinstein (D-Calif.), also have questioned the technical limitations of taking metadata out of the government’s hands.

Obama himself acknowledged Friday the complexities of such a major reform.

“Both of these options pose difficult problems,” he said. “Relying solely on the records of multiple providers, for example, could require companies to alter their procedures in ways that raise new privacy concerns. On the other hand, any third party maintaining a single, consolidated database would be carrying out what is essentially a government function with more expense, more legal ambiguity, and a doubtful impact on public confidence that their privacy is being protected.”

The president then raised the idea that existing authorities could help the government accomplish its goals without maintaining vast stores of metadata, an idea he said had come up during the administration’s internal review, but he gave no additional detail.

His task force appeared to allude to this possibility in its December report. The review group suggested the FCC could lengthen the amount of time it requires telephone companies to retain telephone records, but acknowledged the president couldn’t order an independent agency to make that decision. It also floated the idea of a “voluntary system” to replace the bulk-collection program, but it’s unclear whether telecom companies would agree to such a change.